1. Field of the Invention
The invention relates to an apparatus and method for forming holes in a sheet of a soft, malleable substance, and more particularly, a dough punch for punching multiple openings in a sheet of dough, such as pizza dough.
2. Description of Related Art
The above-referenced application Ser. No. 08/587,912 (U.S. Pat. No. 5,720,998) is directed to a pizza product that includes multiple dough layers. A first dough sheet is placed into a pizza pan or similar utensil, and a food ingredient layer, such as cheese, is placed over the first dough sheet. Then, a second, top dough layer is placed over the first ingredient layer, and a second ingredient layer is placed over the second dough layer. The second ingredient layer can include cheese, sausage, pepperoni and other typical pizza toppings.
The pizza product of the above-referenced application is designed to be baked in a single, continuous baking step. No partial assembly or partial baking steps are required, resulting in significant time savings. To accomplish this, the second dough layer advantageously includes a vent opening that allows steam to escape from the first ingredient layer. According to one embodiment, the vent opening is a single aperture at a central portion of the second dough layer.
It has been found, however, that in many instances the single, central aperture fails to cause steam to escape adequately from the first ingredient layer. For example, steam is generated at a lower boiling point at high altitudes, before the second dough layer has enough time to properly set. This is a problem primarily at altitudes above 3000 feet elevation. Because steam forms earlier, it also is generated for a longer period of time and thus in greater volume. This excess, early steam generated in the first ingredient layer cannot all travel to the central aperture for venting, and can cause a doming effect in the second dough layer. Unattractive bubbling, blistering, and doming in the second dough layer can cause redistribution of the toppings on the second dough layer, even to the point where the toppings slide completely off the pizza. Similar results occur when the first ingredient layer includes food products that have a moisture content that is too high.
Therefore, a need has arisen to prevent distortion to the top dough layer and the second ingredient layer caused by steam generated in the first ingredient layer.